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Scientifically, You Are Likely In the Slowest Line
MojoKid writes "As you wait in the checkout line for the holidays, your observation is most likely correct. That other line is moving faster than yours. That's what Bill Hammack (the Engineer Guy), from the Department of Chemical and Biomolecular Engineering at the University of Illinois — Urbana proves in this video. Ironically, the most efficient set-up is to have one line feed into several cashiers. This is because if any one line slows because of an issue, the entry queue continues to have customers reach check-out optimally. However, this is also perceived by customers as the least efficient, psychologically."
See, you have three checkout lines to choose from. You can't see the register from where you are, but at two of the three lines the cashier is a goat...
This is the norm in Britain. And it works. But trying to get people to do this in the States is like pulling teeth.
That's a shame, since it's obviously the most fair, and eliminates the annoyance of jockeying into different lines to maybe get a faster one. I guess people like the chance of getting lucky occasionally, even at the cost of utility (average wait time) and fairness? Hmmm, our economy makes so much more sense now.
How is that ironic? Doesn't everyone know that? There is no customer configuration in which a single queue isn't more efficient than multiple queues, in average or worst-case waiting time or throughput. You could probably model that and prove it mathematically without needing simulation or experiments.
Watching the video, the conclusion that the video makes is "...You are likely not in the fastest line".
That does not necessarily mean that the reverse (the title) is true -- and yet they somehow jump to that conclusion with the title "...You are likely in the slowest Line."
Can we get some people who actually understand this magical thing called "logic" to start editing Slashdot?
AccountKiller
Its because Frys wants to get a bulk discount from the register repair guy. They wait until 50 of the registers are broken, then call them.
What's this mean? Two thirds of the time at least one neighboring line will be moving faster than you, and you'll curse and stew and froth about your terrible misfortune. But look on the bright side -- two times out of three, at least one of the neighboring queues will have exactly the same burning jealousy towards your swifter, more efficient checkout.
Ironically, the most efficient set-up is to have one line feed into several cashiers.
Alanis Morissette called; she wants her misused word back. Anyway...the above statement ain't necessarily so. What putting everyone into a single queue does is ensure that the distribution of waiting times is very narrow -- everyone will spend very nearly the same amount of time in the queue before reaching a cashier. However, this setup will almost always impair overall checkout efficiency (measured in customers per hour) by some amount; the average waiting time will be slightly longer. Each time a customer clears the cash desk and the cashier has to wait for the next customer to arrive, time is lost. Since the customer can't unpack his basket while the cashier is finishing with the previous customer, time is lost. It gets worse if a customer at the head of the queue doesn't realize that a cashier is available; everyone stands around waiting that extra bit of time. Yes, this can be offset by having a staff member playing shepherd, but that's extra expense for the store (and wouldn't it be better to have that employee actually manning a cash register?). As well, the store needs to be able to maintain a larger open space by the cash registers through which people can move, to get from the head of the queue to the checkout.
In other words, the one-queue system is less efficient in terms of staff costs, less efficient in terms of average customer waiting time, and less efficient in terms of use of floor space. The only advantage is the one alluded to -- it eliminates the slow cashier/slow customer/bad luck penalty, and ensures that everyone has roughly the same wait. (And for that, I actually do prefer this system -- but I don't pretend that it's really more effiicient. I accept that I'm paying a small premium in average waiting time - and writing off a chance to ever be in a lucky fast line - to avoid the risk of occasional long waits.)
~Idarubicin
Let's think about this a bit first. At a place like Costco, you may be trying to feed 20+ registers at a busy time. In terms of average wait time, it's better to have each line constantly full rather than to have someone have to move over to a register and start putting things up on the conveyor belt only after someone else cleared said register. One solution to this is that you specify have exactly one customer waiting behind each register, starting to load goods onto the conveyor belt. First of all, you now have the exact unfairness issue that multiple lines causes since one person might be behind someone with one item, and another behind someone with dozens of items. Might as well let them pick lines since you have the same result anyways, and don't need as much space dedicated to people forming a long line. If you still want to consider a single line, what about those far away stations (there must be at least one register 10 stations away or more)? And what if someone at one of those far away locations only has one or two items? Maybe we should switch to two customers behind each register before forming a big line? And how does a single line affect traffic in the store when you have 40+ people jamming up your main aisle on one side? Maybe we should have a line on each side? Or maybe it's best to let the customers sort through the situation, and just focus on having all open registers used to capacity, as currently is done.
If you have 3 lines, you'd think that 2/3rds of the time there's another line which moves faster. But if you're in a slower line, you're spending more time in that line. So with three lines, you're only in the fastest line for 1/3rd of your purchases. But you're in the fastest line less than 1/3rd of the time. The way Fry's does it with a single queue is pretty much the best way (I can think of an exception for those 10 items or fewer lines).
between single-line multi-server queue and multiple queues.
This occurs in fast food restaurants with the row of cashiers.
This is because some people are "blind" to the fact that there is a single line
situation in effect. These people can be divided into:
1. The generally oblivious. Mindless automatons or cellphone talkers.
2. The socially clueless. Somewhere on the autism spectrum, they don't
understand that queuing is a complex social interaction with rules and etiquette.
3. The obnoxious. Sees the situation but overtly butts in front to stand in front
of one of the cashiers directly, thus forcing others to break rank and sneak in
behind him, since the discipline is shot.
4. The "will be first up against the wall when the revolution comes" devious, who
form their own line like #3 but do it by carefully assessing the situation then actively
pretending that they are in category 1.
So it goes to multiple queues for a while, then some opportunist realizes they
can line up ambiguously in between two cashiers to snag whichever comes open
first, and we're back to single-line til a type 1 to 4 person arrives.
Where are we going and why are we in a handbasket?
Single queues to multiple checkouts work well when the number of checkouts is small and they're close together, and it especially helps if there's a tendency for occasional customers to take much longer than the average. (This happens when there are price checks, arguments over prices, or [in airports] itinerary changes.) It isn't a reasonable option for a WalMart with 40 registers.
And you've actually done the theoretical study of this? People have. Many people. There's even a subspecialty of operations research / computer science / psychology called Queueing Theory.
And the answer really is that a single line works best, even when you include all of the other factors for nearly every situation. If you have a prompter who can anticipate shortly before a given teller will be free, they can even eliminate the travel latency to get from the line to the teller. Naturally, there is an upper limit for fanout, but then it is still the case that a larger queue feeding multiple tellers is more efficient. Always. It is never, ever more efficient to have one line per teller. Ever.
Please, please, please, someone tell the people at US Passport Control about this. The prompter agent always seems to work to keep the small queues in front of each control agent as long as possible when they should be close to zero at all times.
The US Post Office seems to understand the idea, for which I am grateful. Most banks understand this idea as well.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
i pick the line with fewest women in them because they always seem to want to write a check and don't start pulling the checkbook out of their purses until after all items have been scanned... don't want to be sexist but there it is
I love the self service lines...
I hate them. Hire a damn person, clerks aren't that expensive and we have a lot of unemployment. This is not a case of automation being massively more efficient, its just penny pinching and putting people out of work. Plus whenever there is a problem, and they happen often, you have to wait for the one clerk at the kiosk to come over and correct the issue. It amounts to poor service in the name of minimal savings.
"You want to know how to help your kids? Leave them the fuck alone." -George Carlin
I prefer the scan-as-you-pick system, where we pick up a scanner when entering the store, then scan and bag our groceries as we go through the store, and when checking out, simply hand over the scanner and pay. The goods never go on a conveyor belt, and aren't handled by someone who alternates between touching money and food without washing their hands. And you know the total price before you go to the counter. But most of all, it's faster.
Oh, and it's better for the environment too -- you bring your own bags in and out.
I love the self service lines...
I hate them.
Then don't use them. I have never seen a store where they are mandatory.
... putting people out of work.
Please educate yourself.